X- s spark-plug



Vl. W. DRUMMOND.

SPARK PLUG. APPLICATION FILED sEPT.2I, IgIa.

. F Patente June 1T, 1919.

T 0 @il @mit Concern Y MoNn, a citizen of theUnited States, and aresident of hillictlie, in the/county of Ross and State of Ohio, haveinvented certain new and useful Improvements in `Spark- Plugs, of whichthe following is a specification.

My present invention relates generally to spark plugs, and moreparticularly to an anti-fouling plug the structure of which is simple,durable, and efficient, my Aobject be` ing the provision of a plug whichwill develop an extremely hot burning spark and will throw o grease andother carbon producing matter in action.

In the accompanying drawing which illustrates my present invention,

Figure 1 is a side view partly in elevation and partly in sectionshowing a spark plug embodying my invention,

Fig. 2 is an end view thereof, and

Fig. 3 is an end view illustrating a slightly modified form.

Referring now to these figures, my iinprovedy spark plug, as to thegeneral construction of its body, may be of various forms. In thepresent instance, I have shown a spark plug consisting of a shell 10,the inner end of which is externally threaded at 11, and the outer endof which has an external polygonal surface 12 and internal threads 13.This shell has a chamber 14 within its inner. end into which the innerend 15 of the insulatorl projects, and the shell has an intermediatecounter-bore 17 in which the annular enlarged intermediate portion V18of the insulator is seated. The insulator is held by a gasket nut 19which Ascrews within the outer internal threaded end 13 of the shell 10.

A central electrode 20 extends axially through'the insulator 16 as isusual,its inner end projecting axially through the chamber 14 of theshell 10 to a point contiguous to the inner end of the said shell, theouter end of the electrode projecting beyond the outer end of theinsulator 16 being as usual provided with the lead clamping nut 21.

My present invention is applied to the in` ner end of the shell 10 andconsists of a conical orgia frusto-conical electrode 22 which 'tapersinwardly within the chamber 14 and which has an opening 23 through whichthe effective end of the central elec-trode projects, the opposite orlarger end of the said y Specification of Letterslatent.

1 JosErnwaLTanauMMoNn, or cHILLIco'rHE, omo.

-Y SPARK-PLUG;

Patented J une ,l

'f l# application sied september 21, 191s. serial No. zwar/zc.l

electrode 22 'having a flange 24 withinythe" `inner end of the shell 10,whose outer sur-y face is preferably flush with the 'said inner end ofthe shell. A

As seen in Fig. 2, flange 24 is preferably provided with a series ofopenings 25, said series extending yentirely around the electrode 22 inorder to permit ofthe discharge of the burned and powdered carbon fromthe chamber 14, the tapering outer surface of the cone shaped electrode22 acting as a guide to direct the powdered carbon toward the openings25 as it falls. The opening 23 at the smaller end of the cone-shapedelectrode 22 is sufficiently great in diameter as compared to thediameter of the central electrode 20 to bring about aps proximately thecorrect spacing between the electrodes, and extending as it doesentirely around the central electrode, the electrode 22 of the shapedescribed will bring about a 'heavy hot spark which will play entirelyaround the central electrode and will ob` viously burn the carbon asfast as it collectes' posed by my invention is particularly effec tivefor the above purposes, and while it is not essential that the iange 24of the elec trode 22 within the inner end of the shell 10 be providedwith openings 25, as will be seen by reference to Fig. 3 wherein theflange 24L is shown without openings, these openings materially increasethe capacity of the plug to throw off the burned and powdered carbon aspreviously described.

The electrode 22 of the shape and structure described might .be formedintegral with the inner end of the shell 10 but may without complicatingthe manufacture or the said shell, be formed'separate therefrom andeither forced or shrunk therein to the position shown and described.

I claim 1. A spark plug having a cylindrical shell, a main axialelectrode insulated from the shell, and a frustoconical electrodetapering inwardly from the inner end of the shell f2 moans@ and havinganV opening at its Smaller inner end an inwardlyA tapering conicalmember 10 end throughv which the axial electrode forming a secondelectrode, and provided passes, the larger end of the sald 'frustowith aseries vof openings in its said' end conical electrode having a lian efoining the around the larger end of the conical elec- 5 same totheinner end of the s el and protrede, said conical electrode having anopen- -vided with openings therethrough for the ing at its. smallerinner end to receivethe 15 purpose described. l axial electrode, asdescribed.

2. A spark plug inclliding an axial e1ectr0de,' a cylindrical shellhaving at its inner l J OSEPH' WALTER DRUMMOND.-

Uopiel o! this patent may be obtained for ive 'cents each, by addressingthe Commissioner of Patents,

v Washingtom D. c.

